1. Field of the Invention
The present invention relates to an air bubble trapping apparatus which traps an air bubble in a liquid, a liquid transporting apparatus which includes the air bubble trapping apparatus and which transports the liquid, and an ink-jet recording apparatus which records an image etc. on a recording medium by discharging ink from a nozzle onto the recording medium.
2. Description of the Related Art
Among ink-jet recording apparatuses in which a pressure is applied to an ink in a pressure chamber which communicates with a nozzle, and an image and/or a character are recorded on a recording medium by discharging the ink from the nozzle onto the recording medium, there are ink-jet recording apparatuses which are provided with a filter for trapping an air bubble and a foreign matter (impurity) entered and mixed in the ink inside an ink channel, for preventing a decline in a recording quality due to a variation in the pressure in the pressure chamber caused by the air bubble entered in the ink, and/or due to a clog-up of the nozzle caused by the foreign matter entered and mixed in the ink. In such ink-jet recording apparatus, the bubble trapped by the filter is discharged out of the apparatus by purging an ink-jet head when the recording is not performed. However, when a wettability of a surface of the filter is low, the air bubble remains on the surface of the filter even after the purging, and there is a fear that the filter is clogged up.
For solving such problem, in an ink-jet recording apparatus shown in FIG. 7 of U.S. Patent Application Publication No. U.S. 2004/056918A1 (corresponds to FIG. 6 of Japanese Patent Application Laid-open No. 2004-114648), a filter is provided in a buffer tank which supplies an ink to a manifold, and the wettability of the surface of the filter is increased by performing a plasma arc machining (plasma processing) on the surface of the filter. Accordingly, the air bubble hardly remains on the surface of the filter, and by purging the ink-jet head, the air bubble can be discharged assuredly.